England’s Lee Westwood and Canadian David Hearn both carded 66 to be one stroke behind.

Continuing the Australian assault, Jason Day matched the 67 shot by Marcus Fraser, who started with back-to-back bogeys in the morning.

They are tied for fifth with a large group at 3-under, including US Open champion Justin Rose.

Victorian Marc Leishman shot a respectable even-par 70, having conceded he will withdraw from the tournament if his wife Aubrey goes into labour with the birth of their second son. He is level with Western Australian Brett Rumford in a tie for 36th.

Adam ScottSource:AFP

The big question on everyone’s mind this week is whether Tiger Woods can convert his recent scintillating form into his first major title in five years.

The world’s No.1 was out early but could only manage a 1-over 71, which included just two birdies and 14 pars. Two-under through his first 12 holes, Woods finished his round with a disastrous double-bogey 6 at the ninth hole.

"I'm still right there,'' Woods said. "I'm only six back and we have a long way to go."

Woods is tied for 50th alongside newly crowned British Open champion Phil Mickelson.

"Off to a fast start,'' McIlroy said. "Felt like I could shoot a low one. That last four-hole stretch is tough. I didn't play it like I wanted but all things considered it wasn't a bad round.''

tiger woods at PGA ChampionshipSource:Getty Images

Overnight rain had softened the course and provided ideal scoring conditions. However it was still a surprise to see 35 players under par at the end of the first round.

Just three players finished under par the last time the PGA Championship was held at Oak Hill when Shaun Micheel captured the 2003 title. Incidentally, another Queenslander, Rod Pampling, held the first-round lead back then.

Scott was 5-under par through 10 holes when play was temporarily suspended late in the afternoon with lightning in the Rochester, New York area.

At that point, he threatened the Oak Hill course record of 64 – first set by the great Ben Hogan 71 years ago in the 1942 Times-Union Open. Curtis Strange shot 64 on his way to winning the 1989 US Open at Oak Hill.

After a poor opening tee shot, Scott scrambled for a par 4 at the first hole. The 33-year-old made a beautiful up-and-down from the sand to save par at the short third hole.

"I got on a bit of a roll and hit a few shots clean,'' Scott said. "You've got to take advantage of that if it happens because it doesn't happen very often at majors.''

Scott had reigned in Furyk by the eighth hole where he launched a pitching wedge from 142 yards to 10 feet and then rolled in his fifth straight birdie.

Upon resumption from the weather delay, Scott pulled his tee shot left at the par-3 11th. Shortsided and with moist greenside rough, he hit a sublime recovery for the easiest of pars.

He picked up a sixth birdie at the 14th, using his power to take advantage of the drivable 331-yard par 4.

That put him on target for 63, the lowest round in major championship history that has been achieved on 25 separate occasions.

SPO-GLF-MAJ-PGA-CHAMPIONSHIP---ROUND-ONESource:AFP

Alas, Scott bogeyed the 16th, three-putting from 20 metres at the front of the green.

After a wayward blocked tee shot on the 18th, Scott showed his newfound maturity to chop it out and make his par with a pitch-and-putt from the fairway.

That meant he was just one shy of his lowest round in a major, which was the 64 he produced in the opening round of last year’s British Open when he finished second.

Despite the red numbers on the leaderboard, hitting greens is a prerequisite on an Oak Hill layout protected by lush greenside rough. The direction and growth of the grass can leave the world’s best scratching their heads.

In the commentary booth, Ian Baker-Finch observed: “It’s so thick. It’s like Donald Trump’s hair down there. It’s just unbelievable trying to get through that stuff.”

In that regard, Day played one of the shots of the day, holing out with a wedge from just off the 11th green for a birdie 2.